import java.util.Arrays;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 晓星航
 * Date: 2022-12-28
 * Time: 7:57
 */

public class TestDemo {
    public static String func() {
        StringBuffer sb = new StringBuffer();
        return sb.toString();
    }
    public static void main(String[] args) {

    }
    public static void main3(String[] args) {
        StringBuffer sb = new StringBuffer("helloworld");
        System.out.println(sb.delete(0, 5).insert(0, "你好"));
    }
    public static void main2(String[] args) {
        StringBuffer sb = new StringBuffer("helloworld");
        System.out.println(sb.delete(5, 10));
    }
    public static void main1(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("abcdef");
        System.out.println(sb.toString());
    }
}
